In August, Sempra outbid Berkshire for Oncor to move into the Texas power market, which has been more robust because of population growth. That same month, Houston-based Calpine Corp., an independent power producer, agreed to be taken private by a group led by Energy Capital Partners for $17.1 billion in equity and debt.

In October, Dynegy Inc. and Vistra Energy Corp., both in Texas, agreed to merge in a transaction valued at $10.5 billion. The combined company and NRG Energy Inc. would be the only publicly traded merchant-power producers left.

“It’s difficult to have a publicly traded, independent-power producer because of the focus on short-term earnings from a Wall Street point of view,” said Matt Mooren, an energy markets adviser at PA Consulting Group. “With low gas prices and renewables entering the market, that has made the earnings environment a bit more difficult.”

Going South

In Canada, where there aren’t many takeover targets available, utilities went shopping south of the border. Calgary-based AltaGas Ltd. agreed to buy gas-utility owner WGL Holdings Inc. in Washington, D.C., for $6.3 billion. Hydro One Ltd., based on Toronto, agreed to acquire Avista Corp. of Spokane, Washington, for $5.2 billion.

To be sure, not all the deals have been completed. The Public Utility Commission of Texas has yet to sign off on the Oncor-Sempra and Dynegy-Vistra deals. The regulator already nixed an earlier bid by NextEra Energy Inc. to acquire Oncor.

But the industry continues to consolidate. The number of publicly traded utility companies in America has dropped by a quarter over the past decade to about 100, according to data compiled by Bloomberg.

“The market conditions are still favorable from a financing point of view,” said Thomas Flaherty, a senior advisor to Strategy&, a consulting group at PricewaterhouseCoopers LLP. “Money is cheap.”

The quest for growth from predictable, regulated businesses led two of the largest electric companies, Duke Energy Corp. and Southern Co., to acquire natural-gas distributors in 2015. Last month, Eversource Energy bought Aquarion Water Co., calling itself the first U.S.-based electric utility with a water utility.

The deals probably will keep coming this year, with low borrowing costs and more clarity on tax reform, according to a Dec. 14 research note from analysts at JPMorgan Chase & Co.